Which of the following selection markers does pBR322 have?

• pBR322 is a well-known plasmid vector commonly used in molecular biology experiments. It carries two selectable markers:
● Ampicillin resistance (Amp): This gene encodes an enzyme that inactivates the antibiotic ampicillin. Bacteria containing the pBR322 plasmid can survive on media containing ampicillin, while those without the plasmid die.
● Tetracycline resistance (Tet): This gene encodes an enzyme that modifies tetracycline, making it ineffective against the bacteria. Bacteria with the pBR322 plasmid can grow on media containing tetracycline, while those without it cannot.
Therefore, pBR322 possesses both Amp and Tet as selection markers.

📌Other Options:
● Kanamycin resistance (Kan): While some plasmid vectors do contain Kan as a selectable marker, pBR322 does not.

🛑 Related Terminology:
● Selection marker: A gene that allows researchers to identify and select cells containing a specific DNA sequence (in this case, the pBR322 plasmid) by their ability to grow in the presence of a specific antibiotic or other selective agent.
● Plasmid vector: A small, circular piece of DNA that can replicate independently in a host cell and be used to introduce foreign DNA into the host.
● Antibiotic resistance: The ability of a microorganism to resist the effects of an antibiotic.
● Gene encoding: A gene that contains the instructions for making a specific protein.